This study was carried out to analyze the effect of different Bacillus subtilis supplementations on body weight and some dimensions of 35-63 day Noi broilers. A total of 96 Vietnamese native Noi chickens (48 heads for each gender) were allotted into four treatments with three replicates (four heads/ replicate). Treatments included (i) T1: commercial feed GF1324 ad libitum (17% crude protein and 3,000 kcal/kg ME) produced by GreenFeed Vietnam Joint Stock Company, namely GF1324, and free clean water, (ii) T2: GF1324 and free Bacillus subtilis water (0.5g Bacillus subtilis ≥1011 spores/g mixed with 5L clean water) given every Monday from 6:00-18:00, (iii) T3: GF1324 and Bacillus subtilis water provided every Monday and Wednesday from 6:00-18:00, and (iv) T4: GF1324 and Bacillus subtilis water supplied every Monday, Wednesday and Friday from 6:00-18:00. The recorded parameters were not statistically significant different between treatments (P>0.05). This means that the addition of Bacillus subtilis with low and intermittent levels did not change the body weight and dimensions in chickens positively